Cap Assembly and Secondary Battery Including Same

The present application is a Continuation-in-Part of U.S. patent application Ser. No. 19/064,972 filed on Feb. 27, 2025, which claims priority to and the benefit of Korean Patent Application No. 10-2024-0139705, filed on Oct. 14, 2024, in the Korean Intellectual Property Office, the entire disclosures of which are incorporated by reference herein.

Embodiments relate to a cap assembly and secondary battery including same.

Unlike primary batteries that are not designed to be (re)charged, secondary (or rechargeable) batteries are batteries that are designed to be discharged and recharged. Low-capacity secondary batteries are used in portable, small electronic devices, such as smart phones, feature phones, notebook computers, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources for driving motors in hybrid vehicles and electric vehicles and for storing power (e.g., home and/or utility scale power storage). A secondary battery generally includes an electrode assembly composed of a positive electrode and a negative electrode, a case accommodating the same, and electrode terminals connected to the electrode assembly.

The above information disclosed in this Background section is for enhancement of understanding of the background of the present disclosure, and therefore, it may contain information that does not constitute related (or prior) art.

Embodiments are directed to a cap assembly including a cap plate, a terminal plate joined to an opening in the cap plate, and an insulator between the cap plate and the terminal plate, wherein the terminal plate includes a current collector portion electrically connectable to an electrode assembly, and an electrode terminal portion continuously connected to the current collector portion in a longitudinal direction of the terminal plate.

The current collector portion may include a first current collector portion and a second current collector portion that may each be electrically connectable to an electrode assembly, and the electrode terminal portion may be between the first current collector portion and the second current collector portion.

An upper surface of the electrode terminal portion may be higher than an upper surface of the current collector portion in a thickness direction of the terminal plate.

A lower surface of the electrode terminal portion may be higher than a lower surface of the current collector portion in a thickness direction of the terminal plate.

An upper surface of the current collector portion and an upper surface of the electrode terminal portion may face the same direction.

The insulator may include a protrusion portion extending toward the terminal plate and a joining portion joined to the cap plate, and the terminal plate may include a recessed portion engaged with the protrusion portion.

Embodiments are directed to a cap assembly, including a cap plate, a terminal plate coupled to an opening in the cap plate, and an insulator between the cap plate and the terminal plate, the insulator including a peripheral part, a connection part connecting a first side surface of the peripheral part and a second side surface of the peripheral part facing each other in a longitudinal direction of the peripheral part, and a first opening and a second opening each bordered by the connection part and the peripheral part, wherein the terminal plate includes a current collector electrically connectable to an electrode assembly, and an electrode terminal part continuously connected to the current collector in a longitudinal direction of the terminal plate, the current collector includes a first current collector and a second current collector which are electrically connectable to the electrode assembly, the electrode terminal part is between the first current collector and the second current collector, the first current collector borders the first opening and the second current collector borders the second opening, and the connection part is below the electrode terminal part.

The connection part may connect a lower part of the first side surface and a lower part of the second side surface to each other, and the peripheral part and the connection part may be integrally connected.

In a thickness direction of the terminal plate, an upper surface of the electrode terminal part may be higher than an upper surface of the current collector.

In a thickness direction of the terminal plate, a lower surface of the electrode terminal part may be higher than a lower surface of the current collector.

Embodiments are directed to a secondary battery including an electrode assembly including a plurality of electrode plates having a plurality of tabs on one side thereof and a separator between the electrode plates, a case accommodating the electrode assembly and having an opening on one side thereof, and a cap assembly joined to the opening of the case, wherein the cap assembly includes a cap plate, a terminal plate joined to an opening in the cap plate, and an insulator between the cap plate and the terminal plate, and wherein the terminal plate includes a current collector portion electrically connectable to an electrode assembly, and the electrode terminal portion continuously connected to the current collector portion in a longitudinal direction of the terminal plate.

The tabs may be connected to the current collector portion in a bent state.

The tabs may include a first tab and a second tab spaced apart from the first tab, and a bending direction of the first tab may be different from a bending direction of the second tab.

The current collector portion may include a first current collector portion and a second current collector portion that may each be electrically connectable to the electrode assembly, and the electrode terminal portion may be between the first current collector portion and the second current collector portion.

The tabs may include a first tab and a second tab spaced apart from the first tab, the first tab may be connected to the first current collector portion, and the second tab may be connected to the second current collector portion.

An upper surface of the electrode terminal portion may be higher than an upper surface of the current collector portion in a thickness direction of the terminal plate.

A lower surface of the electrode terminal portion may be higher than a lower surface of the current collector portion in a thickness direction of the terminal plate.

An upper surface of the current collector portion and an upper surface of the electrode terminal portion may face the same direction.

The insulator may include a protrusion portion extending into the terminal plate and a joining portion joined to the cap plate, and the terminal plate includes a recessed portion engaged with the protrusion portion.

At least a part of a side surface of the terminal plate that comes into contact with the insulator may be etched and electrolytically treated.

Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout.

Hereinafter, embodiments of the present disclosure will be described, in detail, with reference to the accompanying drawings. The terms or words used in this specification and claims should not be construed as being limited to the usual or dictionary meaning and should be interpreted as meaning and concept consistent with the technical idea of the present disclosure based on the principle that the inventor can be his/her own lexicographer to appropriately define the concept of the term to explain his/her invention in the best way.

The embodiments described in this specification and the configurations shown in the drawings are only some of the embodiments of the present disclosure and do not represent all of the technical ideas, aspects, and features of the present disclosure. Accordingly, it should be understood that there may be various equivalents and modifications that can replace or modify the embodiments described herein at the time of filing this application.

It will be understood that when a layer or element is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. It will be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it may be directly on, connected, or coupled to the other element or layer or one or more intervening elements or layers may also be present. When an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. For example, when a first element is described as being “coupled” or “connected” to a second element, the first element may be directly coupled or connected to the second element or the first element may be indirectly coupled or connected to the second element via one or more intervening elements.

In the figures, dimensions of the various elements, layers, etc. may be exaggerated for clarity of illustration. The same reference numerals designate the same elements. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Further, the use of “may” when describing embodiments of the present disclosure relates to “one or more embodiments of the present disclosure.” Expressions, such as “at least one of” and “any one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. When phrases such as “at least one of A, B and C, “at least one of A, B or C,” “at least one selected from a group of A, B and C,” or “at least one selected from among A, B and C” are used to designate a list of elements A, B and C, the phrase may refer to any and all suitable combinations or a subset of A, B and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively. As used herein, the terms “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by those of ordinary skill in the art.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of example embodiments.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” or “over” the other elements or features. Thus, the term “below” may encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

The terminology used herein is for the purpose of describing embodiments of the present disclosure and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Also, any numerical range disclosed and/or recited herein is intended to include all sub-ranges of the same numerical precision subsumed within the recited range. For example, a range of “1.0 to 10.0” is intended to include all subranges between (and including) the recited minimum value of 1.0 and the recited maximum value of 10.0, that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein, and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited herein. All such ranges are intended to be inherently described in this specification such that amending to expressly recite any such subranges would comply with the requirements of 35 U.S.C. § 112(a) and 35 U.S.C. §132(a).

References to two compared elements, features, etc. as being “the same” may mean that they are “substantially the same”. Thus, the phrase “substantially the same” may include a case having a deviation that is considered low in the art, for example, a deviation of 5% or less. In addition, when a certain parameter is referred to as being uniform in a given region, it may mean that it is uniform in terms of an average.

Throughout the specification, unless otherwise stated, each element may be singular or plural.

Arranging an arbitrary element “above (or below)” or “on (under)” another element may mean that the arbitrary element may be disposed in contact with the upper (or lower) surface of the element, and another element may also be interposed between the element and the arbitrary element disposed on (or under) the element.

In addition, it will be understood that when a component is referred to as being “linked,” “coupled,” or “connected” to another component, the elements may be directly “coupled,” “linked” or “connected” to each other, or another component may be “interposed” between the components”.

Throughout the specification, when “A and/or B” is stated, it means A, B or A and B, unless otherwise stated. That is, “and/or” includes any or all combinations of a plurality of items enumerated. When “C to D” is stated, it means C or more and D or less, unless otherwise specified.

In the present disclosure, the sizes and relative sizes of layers and regions shown in the drawings may be exaggerated for clarity of description. That is, the sizes shown in the drawings are only for convenience of understanding and are not limited thereto. In addition, the same reference numerals denote the same elements throughout the specification.

1 FIG. 1 FIG. 10 10 110 120 110 illustrates an example of a secondary batteryaccording to an embodiment of the present disclosure. Referring to, the secondary batteryaccording to one or more embodiments of the present disclosure may include at least one electrode assembly wound with a separator as an insulator between the positive electrode and the negative electrode, a casein which the electrode assembly is received (or accommodated) therein, and a cap assemblycoupled to an opening of the case.

10 The secondary batteryaccording to one or more embodiments will now be described as an example of a prismatic lithium ion secondary battery. However, the present disclosure is not limited thereto, and suitable aspects, features and principles described herein may be applied to various other types of batteries, such as lithium polymer batteries and/or cylindrical batteries.

Each of the positive electrode and the negative electrode may include a current collector made of a thin metal foil having a coated portion on which an active material is coated and an uncoated portion on which an active material is not coated.

The positive electrode and the negative electrode are wound after interposing the separator, which is an insulator, therebetween. However, the present disclosure is not limited thereto, and the electrode assembly may have a structure in which a positive electrode and a negative electrode, each made of a plurality of sheets, are alternately stacked with a separator interposed therebetween.

110 10 110 The casemay form the overall outer appearance of the secondary batteryand may be made of a conductive metal, such as aluminum, aluminum alloy, or nickel-plated steel. In addition, the casemay provide a space in which the electrode assembly is accommodated.

120 122 110 110 122 130 1 130 2 122 The cap assemblymay include a cap platecovering an opening in the case, and the caseand the cap platemay be made of a conductive material. Terminal plates_and_electrically connected to the positive electrode and the negative electrode, respectively, may be installed to penetrate (or extend through) the cap plateand protrude outwardly therethrough.

122 110 126 122 124 In addition, the cap platemay be made of a thin plate and may be coupled to the opening in the case, and an electrolyte injection port into which a sealing stoppermay be installed may be located (e.g., formed) in the cap plate, and a vent portionhaving a notch may be installed.

130 1 130 2 122 130 1 130 2 130 1 130 2 130 1 130 2 130 1 130 2 130 1 130 2 2 5 FIGS.to In an embodiment, the terminal plates_and_may each be joined to an opening in the cap plate. The terminal plates_and_may each include a current collector portion electrically connectable to the electrode assembly and an electrode terminal portion continuously connected to the current collector portion in the longitudinal direction of the terminal plates_and_. In an implementation, the current collector portion of the first terminal plate_may be connected to a positive electrode of the electrode assembly, and the current collector portion of the second terminal plate_may be connected to a negative electrode of the electrode assembly. In some embodiments, the electrode terminal portion of the first terminal plate_may be a positive electrode terminal, and the electrode terminal portion of the second terminal plate_may be a negative electrode terminal. Examples of the terminal plates_and_are described below with reference to.

10 10 10 The secondary batterymay be, e.g., a lithium battery cell, a sodium battery cell, or the like. However, the secondary batterymay include any battery that is capable of repeatedly providing electricity through charging and discharging. In an embodiment, in a case where the secondary batterymay be a lithium battery cell, the lithium battery cell may be used in electric vehicles (EVs) because the lithium battery cell has excellent lifespan characteristics and high rate characteristics. In an implementation, the lithium battery cell may be used in EVs such as plug-in hybrid electric vehicles (PHEVs). In an implementation, the lithium battery cell may be used in the fields that require a large amount of power storage. In an implementation, the lithium battery cell may be used, e.g., in an electric bicycle, a power tool, and an energy storage system (ESS).

2 FIG. 3 FIG. 4 FIG. 5 FIG. 120 120 120 120 illustrates a perspective view showing an example of the cap assemblyaccording to an embodiment of the present disclosure,illustrates a plan view showing an example of the cap assemblyaccording to an embodiment of the present disclosure,illustrates an exploded perspective view showing an example of the cap assemblyaccording to an embodiment of the present disclosure, andillustrates a cross-sectional view showing an example of the cap assemblyaccording to an embodiment of the present disclosure.

2 4 FIGS.to 1 FIG. 120 210 220 230 240 250 126 220 210 230 210 220 230 210 220 In an embodiment, referring to, the cap assemblymay include, e.g., a cap plate, a terminal plate, an insulator, a vent portion, and an electrolyte injection portin which a sealing stopper (e.g.,of) may be installed. The terminal platemay be joined to the opening in the cap plate. In some embodiments, the insulatormay be between the cap plateand the terminal plate. In some embodiments, the insulatormay be between the cap plateand the inner surface of the opening of the terminal plate.

220 226 220 222 224 222 224 226 222 224 226 222 226 224 In an embodiment, the terminal platemay include current collector portions electrically connectable to the electrode assembly, e.g., configured to electrically connect to the electrode assembly, and an electrode terminal portioncontinuously connected to the current collector portion in the longitudinal direction of the terminal plate. In some embodiments, the current collector portion may include, e.g., a first current collector portionand a second current collector portionthat are electrically connectable to the electrode assembly. In an implementation, the first current collector portionmay be electrically connected to at least a part of the first electrode (or the second electrode) of the electrode assembly, and the second current collector portionmay be electrically connected to at least another part of the first electrode (or the second electrode) of the electrode assembly. The electrode terminal portionmay be between the first current collector portionand the second current collector portion. At least a part of one side surface of the electrode terminal portionmay be connected to the first current collector portion, and at least a part of the other side surface opposite to the one side surface of the electrode terminal portionmay be connected to the second current collector portion.

226 222 224 226 222 224 In an embodiment, the electrode terminal portionmay be continuously connected to the first current collector portionand the second current collector portion. In an implementation, the electrode terminal portionmay be integrally formed (e.g., formed simultaneously in a same process and of a same material to define a monolithic and seamless structure) by using the same metal material or conductive material as the first current collector portionand the second current collector portion.

222 224 222 224 222 224 8 FIG. In an embodiment, the current collector portion (e.g., the first current collector portionor the second current collector portion) may be electrically connected to the electrode tab of the electrode assembly. In some embodiments, the lower surface of the current collector portionsandmay be connected to the electrode tab of the electrode assembly through laser welding or the like. An example in which the electrode assembly and the current collector portionsandare connected is described in detail below with reference to.

222 224 222 224 222 224 222 224 222 224 In an embodiment, the thicknesses of the current collector portionsandmay be determined based on the ease and safety of welding with the electrode tabs of the electrode assembly. In some embodiments, as the thicknesses of the current collector portionsanddecrease, they may be easier to weld with the electrode tab. For example, when the current collector portionsandare slimmer they may be easier to weld to the electrode tab. As the thicknesses of the current collector portionsandincrease, the durability and safety may be improved against external impact or the like. For example, when the current collector portionsandare thicker the durability and safety of the current collector portion against external impact or the like may be improved. In an implementation, considering both the ease of welding with the electrode tab and the improvement of durability and safety, the thickness of the current collector portion may be, e.g., set to 0.1 mm to 3 mm.

222 224 226 220 222 224 226 120 110 222 224 226 1 FIG. In an embodiment, the upper surfaces of the current collector portionsandand the upper surface of the electrode terminal portionmay be exposed to the same side surface in the thickness direction of the terminal plate. For example, the upper surfaces of the current collector portionsandand the upper surface of the electrode terminal portionmay all face the same direction. In some embodiments, in a case where the cap assemblyis joined to the opening of the case (e.g.,of) of the battery cell, the upper surfaces of the current collector portionsandand the upper surface of the electrode terminal portionmay be exposed in the outer direction of the battery cell.

5 FIG. 5 FIG. 5 FIG. 226 222 224 220 226 220 222 224 220 1 226 222 224 220 226 222 224 120 In an embodiment, referring to, the upper surface of the electrode terminal portionmay be higher than the upper surface of the current collector portion (e.g., the first current collector portionor the second current collector portion) in the thickness direction of the terminal plate(e.g., a direction that is parallel with the x axis ofand perpendicular to the y axis of). That is, the upper surface of the electrode terminal portionmay have a protruding shape with a step from the upper surface of the current collector portion in the thickness direction of the terminal plate. The vertical levels of the upper surfaces of the first current collector portionand the second current collector portionmay be equal to each other in the thickness direction of the terminal plate. In an implementation, the distance hbetween the upper surface of the electrode terminal portionand the upper surfaces of the current collector portionsandmay be, e.g., 0.1 mm to 3 mm in the thickness direction of the terminal plate. Accordingly, the upper surface of the electrode terminal portionwith a step from the upper surfaces of the current collector portionsandmay have a form that protrudes toward the outside of the cap assembly, thereby facilitating connection to a busbar for electrical connection between battery cells.

226 222 224 220 222 224 220 2 226 222 224 220 226 222 224 226 226 226 In an embodiment, the lower surface of the electrode terminal portionmay be higher than the lower surface of the current collector portion (e.g., the first current collector portionor the second current collector portion) in the thickness direction of the terminal plate. The vertical levels of the lower surfaces of the first current collector portionand the second current collector portionmay be equal to each other in the thickness direction of the terminal plate. In an implementation, the distance hbetween the lower surface of the electrode terminal portionand the lower surfaces of the current collector portionsandmay be, e.g., 0.1 mm to 3 mm in the thickness direction of the terminal plate. Accordingly, because a separation state between the lower surface of the electrode terminal portion, forming a step with the lower surfaces of the current collector portionsand, and the electrode assembly below the electrode terminal portionmay be maintained, a short between the lower surface of the electrode terminal portionand the electrode assembly may be prevented. In addition, an insulator may be on the lower surface of the electrode terminal portionso as to effectively prevent a short with the electrode assembly.

With this configuration, the terminal plate may be implemented by connecting the current collector portion and the electrode terminal portion continuously or integrally, thereby reducing the number of parts required for manufacturing the secondary battery. In an implementation, because the current path between the current collector portion and the electrode terminal portion may be reduced, the current path between the electrode assembly and the electrode terminal portion may be reduced. Accordingly, the resistance of the conductor in the terminal plate may be reduced and the electrical performance of the secondary battery may be therefore improved. Additionally, by reducing the space between the current collector portion and the electrode terminal portion included in the cap assembly, the size or volume of the electrode assembly that may be accommodated in the case joined to the cap assembly may be increased, and thus, the energy density of the secondary battery may be improved.

6 FIG. 610 620 630 610 620 630 610 620 630 610 illustrates an example in which an insulatorand a terminal plateare joined in an opening of a cap plateaccording to an embodiment of the present disclosure. In an embodiment, the insulatormay be between the terminal plateand the cap plate. In some embodiments, the insulatormay be between one side surface of the terminal plateand one side surface of the cap plate. The insulatormay include an insulating material.

610 612 630 614 620 630 612 612 630 612 620 622 614 614 610 622 620 614 610 620 In an embodiment, the insulatormay include, e.g., a joining portionthat is joined to one side surface of the cap plateand a protrusion portionthat is joined to one side surface of the terminal plate. One side surface of the cap platemay be inserted into the joining portionand engaged with the joining portion. For example, a side surface of the cap platemay extend into and be partially surrounded by the joining portion. In some embodiments, the terminal platemay include a recessed portionthat is engaged with, e.g., partially surrounds, the protrusion portion. In an implementation, the protrusion portionof the insulatormay be inserted into and joined to the recessed portionof the terminal plate. For example, the protrusion portionof the insulatormay extend into the recessed portion of the terminal plate.

620 610 620 620 620 620 620 620 620 620 620 620 620 620 In an embodiment, at least a part of the side surface of the terminal platethat comes into contact with the insulatormay be surface-treated to improve bonding strength. The surface treatment on the side surface of the terminal platemay include etching treatment and electrolytic treatment. In some embodiments, at least a part of the side surface of the terminal platemay be degreased to remove contaminants such as oil present on the surface. In an implementation, the degreasing treatment may be performed using a degreasing solution together with ultrasonic treatment on the side surface of the terminal plate. The ultrasonic treatment may be performed using an ultrasonic cleaner, and the application of the degreasing solution may be performed by stirring and immersing the side surface of the terminal platein the degreasing solution. Thereafter, pores may be formed on the surface of at least a part of the side surface of the terminal plateby using an etching solution. The etching treatment may be performed by stirring and immersing the side surface of the terminal platein the etching solution. In some embodiments, the etching solution remaining on the surface may be removed by heating at least a part of the side surface of the terminal plate. In this case, by performing an anodic oxidation reaction using an electrolyte on at least a part of the side surface of the terminal plate, a coating layer including fine protrusions in the pores in the surface of the terminal platemay be formed. The electrolytic treatment on the side surface of the terminal platemay be performed by causing an anodic oxidation reaction in the electrolyte using the terminal plateas the positive electrode and an insoluble electrode as the negative electrode. During this processing, the electrolyte remaining on the surface of the terminal platemay be removed through heating.

620 610 620 610 610 In an embodiment, the terminal plateon which the etching treatment and the electrolytic treatment have been performed may be joined to the insulatormade of a polymer resin. In an implementation, the terminal plateon which the etching treatment and the electrolytic treatment have been performed may be inserted into a mold and then bonded to the insulatorby injecting and curing the molten polymer resin. The polymer resin used as the material of the insulatormay include, e.g., polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyphthalamides (PPA), polyethylene terephthalate (PET), polycarbonate (PC), polyimide (PI), polyaryletherketone (PAEK), or polyether-ether-ketone (PEEK). The polymer resin may include any one of various polymer resins.

620 610 630 610 620 630 610 620 630 610 620 630 In an embodiment, not only the side surface of the terminal platethat comes into contact with the insulatorbut also the side surface of the cap platethat comes into contact with the insulatormay be surface-treated. The surface treatment method of the terminal platedescribed above may be equally applied to the surface treatment of the cap plate. Accordingly, the insulatorand the terminal platemay be airtightly connected to the opening in the cap plate. For example, the insulatorand the terminal platemay completely seal the opening of the cap plate.

7 FIG. 7 FIG. 1 FIG. 700 700 110 10 illustrates an example of an electrode plateaccording to an embodiment of the present disclosure. The electrode plateshown inmay be a part of an electrode assembly accommodated in the caseof the secondary batteryshown in.

7 FIG. 700 710 720 In an embodiment, referring to, the electrode plateused in the electrode assembly may include, e.g., a coated portionformed by applying a positive electrode active material or a negative electrode active material onto a substrate and an uncoated portion on which no active material is applied. The uncoated portion may be cut by pressing or the like to form a plurality of tabs (or electrode tabs).

720 700 722 724 722 720 700 700 720 700 700 720 700 In an embodiment, the tabson one side of the electrode platemay include, e.g., a first taband a second tabspaced apart from the first tab. In some embodiments, the positions of the tabson one side of the electrode platemay be different depending on the polarity. In an implementation, in a case where the polarity of the electrode plateis positive, the tabsmay be on the upper left side of the electrode plate, and in a case where the polarity of the electrode plateis negative, the tabsmay on the upper right side of the electrode plate.

As the positive electrode active material, a compound capable of reversibly intercalating/deintercalating lithium (e.g., a lithiated intercalation compound) may be used. For example, at least one of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

The composite oxide may be a lithium transition metal composite oxide, and examples thereof may include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free nickel-manganese-based oxide, or a combination thereof.

a 1−b b 2−c c a 2−b b 4−c c a 1−b−c b c 2−α α a 1−b−c b c 2−α α a b c d e 2 a b 2 a b 2 a 1−b b 2 a 2 b 4 a 1−g g 4 (3−f) 2 4 3 a 4 1 As an example, a compound represented by any one of the following formulas may be used: LiAXOD(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiMnXOD(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiNiCoXOD(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiNiMnXOD(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiNiCoLGO(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); LiNiGO(0.90≤a≤1.8, 0.001≤b≤0.1); LiCoGO(0.90≤a≤1.8, 0.001≤b≤0.1); LiMnGO(0.90≤a≤1.8, 0.001≤b≤0.1); LiMnGO(0.90≤a≤1.8, 0.001≤b≤0.1); LiMnGPO(0.90≤a≤1.8, 0≤g≤0.5); LiFe(PO)(0≤f≤2); and LiFePO(0.90≤a≤1.8).

1 In the above formulas: A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and Lis Mn, Al, or a combination thereof.

A positive electrode for a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include a positive electrode active material and may further include a binder and/or a conductive material.

The content of the positive electrode active material is in a range of about 90 wt % to about 99.5 wt % on the basis of 100 wt % of the positive electrode active material layer, and the content of the binder and the conductive material is in a range of about 0.5 wt % to about 5 wt %, respectively, on the basis of 100 wt % of the positive electrode active material layer.

The current collector may be aluminum (Al) but is not limited thereto.

The negative electrode active material may include a material capable of reversibly intercalating/deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of being doped and undoped with lithium, or a transition metal oxide.

The material capable of reversibly intercalating/deintercalating lithium ions may be a carbon-based negative electrode active material, which may include, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon may include graphite, such as natural graphite or artificial graphite, and examples of the amorphous carbon may include soft carbon, hard carbon, a pitch carbide, a meso-phase pitch carbide, sintered coke, and the like.

x A Si-based negative electrode active material or a Sn-based negative electrode active material may be used as the material capable of being doped and undoped with lithium. The Si-based negative electrode active material may be silicon, a silicon-carbon composite, SiO(0<x<2), a Si-based alloy, or a combination thereof.

The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of a silicon particle and amorphous carbon coated on the surface of the silicon particle.

The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core including crystalline carbon and silicon particle and an amorphous carbon coating layer on the surface of the core.

8 FIG. 8 FIG. 7 FIG. 810 820 810 700 812 814 810 812 814 810 illustrates an example in which an electrode assemblyis connected to a terminal plateaccording to an embodiment of the present disclosure. In an embodiment, referring to, the electrode assemblymay include, e.g., a plurality of electrode plates (e.g.,of) having a plurality of tabs formed on one side thereof and a separator between the electrode plates. A plurality of first tabsand a plurality of second tabsmay be protruded and aligned, e.g., aligned with each other, on one side of the electrode assembly. The first tabsand the second tabsmay be spaced apart from each other at a certain interval on one side of the electrode assembly.

810 820 820 220 820 822 824 810 826 826 822 824 820 2 6 FIGS.to In an embodiment, the electrode assemblymay be electrically connected to the terminal plate. The terminal platemay correspond to the terminal platedescribed above with reference to. The terminal platemay include, e.g., a first current collector portion, a second current collector portion, which may be electrically connectable to the electrode assembly, and an electrode terminal portion. The electrode terminal portionmay be continuously or integrally connected to the first current collector portionand the second current collector portionin the longitudinal direction of the terminal plate.

826 820 822 824 812 822 814 824 812 814 826 820 822 824 826 812 814 826 822 824 826 In an embodiment, the electrode terminal portionof the terminal platemay be between the first current collector portionand the second current collector portion. In some embodiments, the first tabsmay be connected to the first current collector portion, and the second tabsmay be connected to the second current collector portion. The separation distance between the first tabsand the second tabsmay correspond to the length of the electrode terminal portionin the longitudinal direction of the terminal plate. In this configuration, the first current collector portionand the second current collector portion, which may be respectively connected to opposite sides of the electrode terminal portion, may correspond to the positions of the first tabsand the second tabs. Additionally, because the lower surface of the electrode terminal portionmay be higher than the lower surfaces of the first current collector portionand the second current collector portion, a short between the electrode terminal portionand the tabs may be prevented.

810 820 812 814 812 814 822 824 812 814 832 812 822 810 834 814 824 810 832 834 8 FIG. In an embodiment, the electrode assemblymay be electrically connected to the terminal platethrough the first tabsand the second tabs. In some embodiments, the first tabsand the second tabsmay be respectively connected to the first current collector portionand the second current collector portionin a bent state. The bending direction of the first tabsmay be different from the bending direction of the second tabs. For example, referring to, a first welded portionmay be formed by welding the first tabsto the first current collector portionin a state of being collectively bent toward the first side surface of the electrode assembly. In addition, a second welded portionmay be formed by welding the second tabsto the second current collector portionin a state of being collectively bent toward the second side surface opposite to the first side surface of the electrode assembly. The first welded portionand the second welded portionmay be formed through ultrasonic welding.

With this configuration, the first tabs and the second tabs may be bent in different directions and respectively connected to two current collector portions connected to opposite sides of the electrode terminal portion of the terminal plate. Accordingly, even in a case where one of the tabs formed on one electrode plate (e.g., two tabs bent in opposite directions) is not connected to the terminal plate, another one of the tabs may be connected to the terminal plate. In some embodiments, a pair of tabs formed on one electrode plate may have a complementary connection structure with respect to the terminal plate. Accordingly, even in a case where the length of the tabs of the electrode plate is shortened so as to increase the capacity of the secondary battery, the electrical safety of the secondary battery may be improved because the tabs of the electrode plate may be effectively connected to the terminal plate.

9 FIG. 920 920 910 930 910 920 illustrates an example of a terminal plateaccording to an embodiment of the present disclosure. In an embodiment, the terminal platemay be joined to an opening formed in a cap plate. In some embodiments, an insulatormay be between the cap plateand the terminal plate.

920 922 924 922 920 924 922 920 924 922 920 In an embodiment, the terminal platemay include, e.g., a current collector portionelectrically connectable to an electrode assembly, and an electrode terminal portioncontinuously or integrally connected to the current collector portionin the longitudinal direction of the terminal plate. The upper surface of the electrode terminal portionmay be higher than the upper surface of the current collector portionwith a step in the thickness direction of the terminal plate. The lower surface of the electrode terminal portionmay be higher than the lower surface of the current collector portionand form a step in the thickness direction of the terminal plate.

920 930 920 926 922 930 928 924 930 920 930 6 FIG. In an embodiment, the terminal platemay include a recessed portion engaged with the insulator. In some embodiments, the terminal platemay include a first recessed portionin which the current collector portionand the insulatorare engaged with each other, and a second recessed portionin which the electrode terminal portionand the insulatorare engaged with each other. The method in which the terminal plateis engaged with the insulatormay be similar to that described above with reference to.

10 FIG. 11 FIG. 10 FIG. 1 FIG. 120 120 120 1010 1020 1030 1040 1050 126 1020 1010 is an illustration of an exploded perspective view showing a cap assemblyA according to an embodiment of the present disclosure, andis a cross-sectional view illustrating the same example of the cap assemblyA. In an embodiment, referring to, the cap assemblyA may include a cap plate, a terminal plate, an insulator, a vent part, and an electrolyte injection holein which a sealing stopper, e.g., sealing stopperof, may be installed. Here, the terminal platemay be coupled to an opening formed in the cap plate.

1030 1032 1010 1020 1034 1032 1032 1032 1030 1036 1038 1034 1036 1038 10 FIG. An insulatormay include a peripheral partbetween a cap plateand a terminal plate, and a connection partconnecting a first side surface of the peripheral partA and a second side surface of the peripheral partB facing each other in a longitudinal direction of the peripheral part. The insulatormay include a first openingand a second openingformed by the connection part. For example, as may be seen in, the first openingand the second openingmay be distinct openings each boarded by the connection part and the peripheral part.

1034 1030 1032 1032 1032 1032 1034 1032 1010 1020 1032 1010 1020 The connection partof the insulatormay connect a lower part of a first side surface of the peripheral partA and a lower part of a second side surface of the peripheral partB, which may face each other in a longitudinal direction of a peripheral part, and the peripheral partand the connection partmay be integrally formed by an injection process. The peripheral partmay be between the inner surface of the openings of the cap plateand the terminal plate. In an implementation, the peripheral partmay be between the cap plateand an inner surface of an opening of the terminal plate.

1030 1030 In an embodiment, the insulatormay include a material having electrical insulation, e.g., is an electrical insulator, and thermal conductivity. In an implementation, the insulatormay include, e.g., a ceramic with excellent thermal conductivity, aluminum nitride (AlN, Aluminum Nitride), alumina (Alumina, Aluminum Oxide), boron nitride (BN, Boron Nitride), or aluminum metal powder.

1030 1030 1020 1022 1024 1026 1020 In an embodiment, the insulatormay lower a physical percolation threshold by controlling an aspect ratio of a metal or ceramic and characteristics of a ceramic-polymer interface, and accordingly, may improve thermal conductivity. In an implementation, thermal conductivity may be improved by precisely controlling defects in a crystal of the insulator, a dispersion structure, interface characteristics, or an aspect ratio. In an embodiment, the terminal platemay include, e.g., current collectorsandwhich may be electrically connectable to an electrode assembly, and an electrode terminal partcontinuously connected to the current collector in a longitudinal direction of the terminal plate.

1022 1024 1022 1024 1026 1022 1024 1026 1022 1026 1024 Specifically, the current collector (e.g., current collector portion) may include a first current collectorand a second current collectorwhich may be electrically connectable to the electrode assembly. In an implementation, the first current collectormay be electrically connected to at least a portion of a first electrode (or a second electrode) of the electrode assembly, and the second current collectormay be electrically connected to at least another portion of the first electrode (or the second electrode) of the electrode assembly. Here, the electrode terminal partmay be between the first current collectorand the second current collector. At least a portion of one side surface of the electrode terminal partmay be connected to the first current collector, and at least a portion of the other side surface opposite to the one side surface of the electrode terminal partmay be connected to the second current collector.

1026 1022 1024 1026 1022 1024 In an embodiment, the electrode terminal partmay be continuously connected to the first current collectorand the second current collector. In an implementation, the electrode terminal partmay be manufactured integrally using the same metal material or conductive material as the first current collectorand the second current collector.

1022 1036 1030 1024 1038 1030 In an embodiment, the first current collectormay be coupled to, e.g., may border, the first openingof the insulator, and the second current collectormay be coupled to, e.g., may border, the second openingof the insulator.

1034 1030 1026 1030 1022 1024 1026 1026 120 1026 1030 1026 In an embodiment, the connection partof an insulatormay be below the electrode terminal part. Accordingly, a short with an electrode assembly may be effectively prevented. In an implementation, by applying the insulatorwith excellent thermal conductivity, heat that may be generated by concentration of current in current collectorsandand the electrode terminal partmay be effectively dissipated. In particular, because a temperature of the electrode terminal partmay be the highest part, e.g., the temperature of the cap assemblyA may be the greatest at the electrode terminal part, presence of the insulatorwith excellent thermal conductivity below the electrode terminal partmay itself be effective for heat dissipation.

1022 1024 In an embodiment, a current collector (e.g., a first current collectoror a second current collector) may be electrically connected to an electrode tab of an electrode assembly. Specifically, a lower surface of the current collector may be connected to the electrode tab of the electrode assembly through laser welding or the like.

1022 1024 1022 1024 1022 1024 In an embodiment, a thickness of current collectorsandmay be determined based on ease and safety of welding with an electrode tab of an electrode assembly. Specifically, as the thickness of the current collectorsandis smaller, welding with the electrode tab may be easier, and as the thickness of the current collectorsandis larger, durability and safety due to an external impact or the like may be improved. In an implementation, a thickness of the current collector may be set to 0.1 mm to 3 mm in consideration of both ease of welding with an electrode tab and improvement of durability and safety.

1020 1022 1024 1026 120 110 1022 1024 1026 1 FIG. In an embodiment, in a thickness direction of the terminal plate, an upper surface of current collectorsandand an upper surface of an electrode terminal partmay be exposed to the same side. In an implementation, when the cap assemblyA is coupled to an opening of a case of a battery cell (e.g., the caseof), the upper surface of the current collectorsandand the upper surface of the electrode terminal partmay be exposed to the exterior outward direction of the battery cell.

11 FIG. 1020 1026 1022 1024 1020 1026 1020 1022 1024 1020 1 1026 1022 1024 1026 1022 1024 120 Referring to, in a thickness direction of a terminal plate, an upper surface of an electrode terminal partmay be located higher than an upper surface of a current collector (e.g., a first current collectoror a second current collector). That is, in the thickness direction of the terminal plate, the upper surface of the electrode terminal partmay have a protruding shape with a step from the upper surface of the current collector. In the thickness direction of the terminal plate, vertical levels of upper surfaces of the first current collectorand the second current collectormay be same as each other. In an implementation, in the thickness direction of the terminal plate, a distance hbetween the upper surface of the electrode terminal partand an upper surface of the current collectorsandmay be 0.1 mm to 3 mm. Accordingly, the upper surface of the electrode terminal parthaving a step with the upper surface of the current collectorsandmay have a shape such they protrude toward the outside of, e.g., away from, the cap assemblyA, and may be easily connected to a busbar for electrical connection between battery cells.

1020 1026 1022 1024 1020 1022 1024 1020 2 1026 1022 1024 1026 1022 1024 1026 In an embodiment, in a thickness direction of a terminal plate, a lower surface of an electrode terminal partmay be located higher than a lower surface of a current collector (e.g., the first current collectoror the second current collector). Here, in the thickness direction of the terminal plate, vertical levels of lower surfaces of the first current collectorand the second current collectormay be same as each other. In an implementation, in the thickness direction of the terminal plate, a distance hbetween the lower surface of the electrode terminal partand a lower surface of the current collectorsandmay be 0.1 mm to 3 mm. Accordingly, a spaced state between the lower surface of the electrode terminal parthaving a step with the lower surface of the current collectorsandand an electrode assembly located below the electrode terminal partmay be maintained.

1034 1026 1026 1034 1034 The connection partmay be below the electrode terminal part. A thickness of the electrode terminal partand the connection partmay be greater than or equal to 2 mm in consideration of rigidity. The thickness of the connection partmay be greater than or equal to 1 mm to facilitate ease of injection, but is not limited thereto.

1020 1034 1022 1024 1034 1022 1024 1022 1024 In an embodiment, in a thickness direction of a terminal plate, a vertical level of a lower surface of a connection partmay be same as a vertical level of a lower surface of current collectorsand. In an implementation, there may be a step between the lower surface of the connection partand the lower surface of the current collectorsand. In this case, a range of the step may be determined according to a distance (e.g., 0.2 mm to 1.5 mm) between the current collectorsandand an electrode assembly.

Due to this configuration, by implementing a terminal plate by continuously or integrally connecting a current collector and an electrode terminal part, a number of components required for manufacturing a secondary battery may be reduced. In addition, because a current path between the current collector and the electrode terminal part is reduced, a current path between an electrode assembly and the electrode terminal part may be reduced. Accordingly, because a conductor of resistance is reduced in the terminal plate, electrical performance of the secondary battery may be improved. In addition, because a space between the current collector included in a cap assembly and the electrode terminal part is reduced, a size or a volume of the electrode assembly that may be accommodated inside a case coupled to the cap assembly may be increased, and accordingly, an energy density of the secondary battery may be improved.

12 FIG. 13 FIG. 12 FIG. 13 FIG. 12 FIG. 13 FIG. 1030 1030 1034 1030 1034 1030 1034 1 1034 2 1034 3 1030 1030 is a diagram illustrating an example of an insulatorA according to an embodiment of the present disclosure, andis a diagram illustrating an example of an insulatorB according to another embodiment of the present disclosure. Referring to, a connection partA of an insulatorA may be formed in a mesh type. Referring to, a connection partB of an insulatorB may include a plurality of legsB,B, andB. By providing the insulatorA ofor the insulatorB of, while material use of the insulator is reduced, a short between a lower surface of an electrode terminal part and an electrode assembly may be effectively prevented.

By way of summation and review, the electrode terminal of the secondary battery may be connected to the electrode assembly through a current collector plate between the electrode assembly and the electrode terminal. However, the current collector plate may lengthen the current path between the electrode assembly and the electrode terminal, which may increase the resistance of the conductor. Accordingly, the performance of the secondary battery may be deteriorated.

According to some embodiments of the present disclosure, because the current collector and the electrode terminal portion may be connected continuously or integrally, the number of parts required for manufacturing the secondary battery may be reduced.

According to some embodiments of the present disclosure, because the current collector and the electrode terminal portion may be connected continuously or integrally, the current path between the current collector and the electrode terminal portion may be reduced, and thus, the current path between the electrode assembly and the electrode terminal portion may be reduced. Accordingly, because the resistance of the conductor may be reduced, the performance of the secondary battery may be improved.

According to some embodiments of the present disclosure, the energy density of the secondary battery may be improved by omitting or reducing the space between the current collector and the electrode terminal portion.

According to some embodiments of the present disclosure, because the first tabs and the second tabs may be bent in different directions and connected to the terminal plate, at least one of the tabs formed on one electrode plate may be connected to the terminal plate. Accordingly, even in a case where the length of the tab of the electrode plate is shortened, the tab of the electrode plate may be connected to the terminal plate, and thus, the electrical safety of the secondary battery may be improved.

These and other aspects and features of the present disclosure are described in or are apparent from the above description of embodiments of the present disclosure.

However, aspects and features of the present disclosure are not limited to those described above, and other aspects and features not mentioned will be clearly understood by a person skilled in the art from the detailed description, described above.

Although the present disclosure has been described above with respect to embodiments thereof, the present disclosure is not limited thereto. Various modifications and variations can be made thereto by those skilled in the art within the spirit of the present disclosure and the equivalent scope of the appended claims.

Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.